Really depends on a few thing if your own engine is a failure or something else . If putting back to standard then , strip down and inspect the block,crank , heads , Pistons ,that there good to reuse , and if there checked and all ok your just into Engine Gasket kit, bearing kit , head gasket, head studs , Timing belt kit various oil and filters and labour . that's best case Your looking at 2500/3500
after that then it's up to you how much you want to spend . If you need a new crank , pistons second hand block , all really an unknown till your engine is striped if your using it .
You could also buy a new shortblock and bolt your heads to it if your own block was beyond fixing there are loads of options with differant prices , but there are very few cheap fixes if your doing it right
Pick a figure your happy to spend on the engine and that will decide what way you will go with the build